I want to handle Big Integer (greater than 2^63) in C++. I know that, I need to use string to perform it. But I have no idea about how to write a program which can handle a big integer. Can anyone please help me about handling big integer?
I know how to handle big number addition, subtraction, multiplication and division. But I am frustrate to handle just only one big number with a size up to 2^63. I understand that 1st I need to declare a string variable, than work with the size of the variable. I need to convert the string variable value into integer and finally save the results of my desire work in a string variable. But how can I convert the value of a string into integer (no need to use atoi() function)? How can I convert the results of my work from integer to string?